The present invention relates to a method and apparatus for pinpointing the causes of malfunction of machines for the manufacture and/or processing of cigarettes and/or other commodities which constitute or form part of smokers' products. More particularly, the invention relates to a method and apparatus for ascertaining those conveyors, guides, tubes and/or other components of machines for the manufacture and/or processing of smokers' products which influence or can influence the quality of such products. Still more particularly, the invention relates to a method and apparatus for ascertaining (and preferably pinpointing) those changes in the characteristics and/or condition of certain components of one or more machines for the manufacture and/or processing of smokers' products which are likely to or invariably exert an adverse influence upon the quality of smokers' products, especially rod-shaped articles including plain or filter tipped cigarettes, cigars or cigarillos, filter rod sections or the like.
Many types of machines for the production and/or processing of smokers' products are prone to malfunction. This is due to the extremely high output of such machines (recent types of cigarette makers can turn out in excess of 100 cigarettes per second), to unpredictable changes in the characteristics (moisture content, particle size, specific weight, etc.) of natural, reconstituted or substitute tobacco, to complexity of machines, to inept and/or careless handling of machines, and/or other factors. For example, particles of tobacco are likely to clog the suction ports of rotary conveyors which are used in many types of cigarette makers and filter tipping machines so that the ports cannot properly attract tobacco shreds, unwrapped tobacco fillers, wrapped fillers, filter plugs, plain cigarettes or filter cigarettes. Also, adhesive paste is likely to contaminate conveyors or other machine components which come into contact with cigarette paper webs, uniting bands, wrappers of plain or filter cigarettes or other adhesive-coated or adhesive-containing parts of smokers' products. Still further, filter rod sections or portions thereof (e.g., filter plugs of double unit length) are likely to be wedged in the guides, flutes or other portions of machine parts in a filter rod making, filter rod propelling or filter tipping machine. Finally, parts of such machines can become inoperative as a result of wear, as a result of improper maintenance and/or for other reasons to necessitate at least short-lasting stoppage or reduction in the speed of the respective machine until the damaged machine part is replaced or repaired. The aforediscussed defects of conveyors and/or other machine parts must be eliminated without delay because they are highly likely to and normally do affect the quality of smokers' products.
As a rule, at least certain types of smokers' products are tested prior to introduction into a packing machine or into storage. For example, plain or filter cigarettes are tested to ascertain the condition of their wrappers and/or tobacco-containing ends. Cigarettes wherein the permeability of wrappers and/or the density of tobacco-containing ends is excessive or too low are segregated from other (satisfactory) cigarettes. When the number of rejects reaches or exceeds a certain percentage of the total output of a cigarette maker or filter tipping machine, the machine or the testing device generates a signal to warn the attendants or automatically stops the main prime mover. By examining the defective cigarettes, an experienced attendant is likely to rapidly ascertain the cause of production of excessive numbers of rejects. In many instances, simple cleaning of a conveyor or the like to remove tobacco dust, larger fragments of tobacco leaves, squashed filter plugs, dried adhesive paste or the like suffices to restore the respective components to their operative condition.
However, in many instances, the search for the cause of malfunction of a machine for the making and/or processing of smokers' products (hereinafter called cigarettes) is a tedious and time-consuming task, even if such task is performed by a highly skilled and careful attendant. Losses in output are extremely high, i.e., losses in the output of a cigarette maker often amount to tens and hundreds of thousands of articles.
In accordance with a presently known proposal, those components of a machine for the manufacture and/or processing of cigarettes which are most likely or more likely to become partly or fully inoperative are equipped with mechanical, electronic or other types of sensors (as a rule, the sensors monitor the products or parts of products in or on the selected components) which generate signals in response to detection of malfunction or inferior products. For example, a sensor can generate a visible or audible signal when the filter plug of a filter cigarette is missing, when the quantity of adhesive in the seam of the wrapper of a cigarette is too low or excessive, when the wrapper exhibits a large hole, when a web of cigarette paper is defective or for other reasons. The attendant notes the signal (e.g., a lighted lamp) at a point which is remote from the defective component and proceeds to rapidly eliminate the cause of defects.
The installation of numerous sensors in a cigarette making or processing machine could greatly reduce the downtimes by enabling the attendants to pinpoint the causes of malfunction with a minimum of delay. However, the number of sensors which can be installed at a reasonable cost and without interfering with normal operation of the machine is evidently limited. Furthermore, the installation of lamps or other signal generating devices next to the respective sensors or machine components would result in further crowding of the machine and would contribute significantly to sensitivity and maintenance cost of such machine. Therefore, the just discussed proposal failed to gain widespread acceptance in the industry, mainly because its remedial action is not all-embracing.
U.S. Pat. No. 3,242,321 granted Mar. 22, 1966, to Henry R. Chope proposes to combine a testing device with several detectors which monitor vibrations of selected conveyors or other components of a machine in such a way that, when the quality of tested products is less than satisfactory, the detectors are addressed in a given sequence to ascertain whether or not the vibratory movements of corresponding components are normal. If the vibrations of a component are different from normal, the detector-addressing circuit causes one of several lamps to transmit a visible signal and to thus pinpoint the presumably defective component. The patent mentions that the just discussed system can be installed in a cigarette maker. However, applicants and their assignee are not aware of any cigarette makers or other machines for the manufacture or processing of smokers' products which incorporate such system or a similar arrangement for rapid detection of components which cause a lowering of the quality of the ultimate product or products.
A highly likely reason for the absence of a system of vibration detectors in a cigarette maker or a similar or related machine is that a filter plug which is wedged in a stationary guide or the adhesive-contaminated tubular guide of a cutoff for plain or filter cigarettes or filter plugs is quite unlikely to cause detectable changes in vibration of the respective machine components. First of all, the machines for mass-production of smokers' products are sturdy, so that the presence of dried adhesive or of a jammed filter plug is not supposed to change the frequency and/or amplitude of vibrations of affected components. Secondly, detection of minute changes of vibrations would necessitate resort to highly sensitive detectors which would contribute excessively to the initial and/or maintenance cost of the machine.